when and how do i bleed my pump
- Thread starter mgally
- Start date
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thanks for all your ideas....and banter.
Just to clarify.
the hot water is definately rising up the 15mm feed pipe into the f/e tank for the c/h cistern (i can feel the red hot water entering when i put my hand down into the tank). the cold water storage tank for dhw is unaffected...and it sits a little higher than the c/h cistern.
there is a 22mm expansion pipe along side the 15mm feed pipe but the hot water is going up the feed pipe instead, i have drained the system down to check for a blockage around this area but its clear....the 15mm pipe is nearer to the pump than the expansion pipe albeit they are along side each other.....they are situated about a foot before the pump on the hot water feed from the boiler.
the reason i thought 'pump' was that ive tried everything else and when i put the pump to speed one the situation gets worse, so i was thinking that the hot water is backing up at the pump, which cant shift the water fast enough, and finding an easy escape.
the pump responds well and all rads get fine and hot, cylinder water gets fine and hot, room stat and cylinder stat working fine, what else can it be ?
i have even lowered the ballcock in the f/e tank to a level where the tank is only a third full....so we are talking a lot of water to make it overflow !
the overflow starts pouring out when the central heating is just getting to a decent temp, about 15 mins after the system fires up.....it pours out for a few mins then stops.
im at a complete loss......mike
Just to clarify.
the hot water is definately rising up the 15mm feed pipe into the f/e tank for the c/h cistern (i can feel the red hot water entering when i put my hand down into the tank). the cold water storage tank for dhw is unaffected...and it sits a little higher than the c/h cistern.
there is a 22mm expansion pipe along side the 15mm feed pipe but the hot water is going up the feed pipe instead, i have drained the system down to check for a blockage around this area but its clear....the 15mm pipe is nearer to the pump than the expansion pipe albeit they are along side each other.....they are situated about a foot before the pump on the hot water feed from the boiler.
the reason i thought 'pump' was that ive tried everything else and when i put the pump to speed one the situation gets worse, so i was thinking that the hot water is backing up at the pump, which cant shift the water fast enough, and finding an easy escape.
the pump responds well and all rads get fine and hot, cylinder water gets fine and hot, room stat and cylinder stat working fine, what else can it be ?
i have even lowered the ballcock in the f/e tank to a level where the tank is only a third full....so we are talking a lot of water to make it overflow !
the overflow starts pouring out when the central heating is just getting to a decent temp, about 15 mins after the system fires up.....it pours out for a few mins then stops.
im at a complete loss......mike
Why does everyone insist on calling the vent pipe the expansion pipe? The 15mm pipe is the feed & expansion pipe.mgally said:
As for being at a complete loss, this is odd since we've explained at length exactly what the problem is likely to be. Perhaps Mike should read the posts again?
If you turn off the isolating valve (gatevalve) on the feed pipe from the cold feed tank to the HW cylinder and then open a hot tap until it stops running, you should find that the water level in the CH F&E tank stops rising and dfalls instead as it leaks from the cylinder coil into the cylinder.
B
Bamber gaspipe
mgally said:
Blockage / sticking pump
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Rob884 got it in one right at the beginning (sharp, isn't he!).rob884 said:
If the tank overflows only while the system water is expanding (as OP has finally informed us
), then it's just normal expansion taking place but with the F&E tank water level too high when cold so expansion cannot be accommodated before the overflow level is reached. So not a blockage or sticking pump at all, Bamber.
Bamber, it's not meant to be a competition to see who's right and who's wrong. We are just trying to identify possible causes for the symptoms described.Bamber gaspipe said:
On the basis of the rather limited information given, it looked like it might be an overfilled F&E tank or a leak from cylinder into coil. Rob identified both those at the outset. I simply offered further explanation.
Your one useful contribution was to highlight the last morsel of info given by the OP's last post which I had overlooked (yes, my mistake - I'll admit to that if it makes you happy) and which tends to support the overfilled F&E tank theory.
But since we're not getting any feedback from the OP we can't get any further with confirming what the problem is. Anyway I'm afraid your theory of a blockage and pumping over never really stacked up.
hysterical.......advice and entertainment, what more can you ask for.
ill drop the ballcock level to see if it does the job as it seems the most plausible explaination.....my only concern is why this problem has emerged now, the system has worked fine for 4 years with no overflow problems.
many thanks.....Mike (wirral...uk)
ill drop the ballcock level to see if it does the job as it seems the most plausible explaination.....my only concern is why this problem has emerged now, the system has worked fine for 4 years with no overflow problems.
many thanks.....Mike (wirral...uk)
mgally, rob884 identified the two possible causes right at the outset, and I haven't read anything in your posts that has yet eliminated either of his suggestions. However, this:
...confirms that the you have a damaged coil. So this idea:On October 16 said:
...will achieve nothing.mgally said:
Nothing lasts forever. It's the fundamental nature of faults to be absent one moment and present the moment after. When things go wrong it's nearly always out of the blue, so the fact that it's been working for 4 years simply means that your cylinder is four years nearer the end of its operational life.
B
Bamber gaspipe
Post deleted
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Will you boys please try to find a hobby that doesn't involve being rude to each other at great length on here.
Mod Rupert
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Will you boys please try to find a hobby that doesn't involve being rude to each other at great length on here.
Mod Rupert
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In amongst all the excitement (!!), others have omitted to explain fully what's likely to have happened.
(Assuming that the F&E tank overflow is LOWER than the water level in the (larger) cold water storage tank...)
The coil in an 'indirect' hot water cylinder is usually hard-soldered to fittings that penetrate the outer wall of the cylinder. This is the commonest point of failure, due to careless installation, over-tightening of the compression fittings outside the cylinder, strained pipes putting stress on the coil joints by bending the bosses out-of-alignment, or simply age and corrosion.
Once there is a water path from the cylinder into the coil, water will flow one way or the other, depending on relative pressure. Where there is an F&E tank mounter LOWER than the cold water tank, water will flow INTO the primary heating circuit from the cylinder and the F&E will overflow. In a sealed system (no F&E tank), it will not be possible to maintain pressure in the system because water will be forced into the cylinder and back up into the cold water tank.
Complete replacement of the cylinder is the only practical option.
[there should be a Wiki entry on this topic]
(Assuming that the F&E tank overflow is LOWER than the water level in the (larger) cold water storage tank...)
The coil in an 'indirect' hot water cylinder is usually hard-soldered to fittings that penetrate the outer wall of the cylinder. This is the commonest point of failure, due to careless installation, over-tightening of the compression fittings outside the cylinder, strained pipes putting stress on the coil joints by bending the bosses out-of-alignment, or simply age and corrosion.
Once there is a water path from the cylinder into the coil, water will flow one way or the other, depending on relative pressure. Where there is an F&E tank mounter LOWER than the cold water tank, water will flow INTO the primary heating circuit from the cylinder and the F&E will overflow. In a sealed system (no F&E tank), it will not be possible to maintain pressure in the system because water will be forced into the cylinder and back up into the cold water tank.
Complete replacement of the cylinder is the only practical option.
[there should be a Wiki entry on this topic]
Croydoncorgi, that's a good explanation of the leaking cylinder coil theory, but the later posting from the OP suggests that this is not the right explanation.
Note that he says the overflow starts 15 mins after heating switches on and then stops a while later, suggesting that it is expansion related (which would also result in hot water travelling up F&E pipe - perfectly normal in that context).
On the other hand the OP says that the F&E tank water level when cold is quite low, so how would expansion be enough to reach the overflow level, unless it's a very big system?
Of course it might be multiple faults.........
Note that he says the overflow starts 15 mins after heating switches on and then stops a while later, suggesting that it is expansion related (which would also result in hot water travelling up F&E pipe - perfectly normal in that context).
On the other hand the OP says that the F&E tank water level when cold is quite low, so how would expansion be enough to reach the overflow level, unless it's a very big system?
Of course it might be multiple faults.........
I once replaced a very tall cylinder in a very tall house, where the F&E level wasn't rising at all.
The symptoms of the faulty coil were a high-pitched 'squirting' noise from the cylinder, and the return never getting hot.
My point is that the symptoms aren't always the same, although the most common symptom is a steadily running overflow.
The symptoms of the faulty coil were a high-pitched 'squirting' noise from the cylinder, and the return never getting hot.
My point is that the symptoms aren't always the same, although the most common symptom is a steadily running overflow.
B
Bamber gaspipe
chrishutt said:
tank & f&e doing it`s job, blockage
or pump failure Maybe somewhere there's s HUGE amount of air getting heated up and expanding.....
Have all the rads been properly bled (with CH OFF)?
And does the level in the F&E drop a long way from the overflow point as the system cools? (Without a large air volume present somewhere, this sounds unlikely....).
Have all the rads been properly bled (with CH OFF)?
And does the level in the F&E drop a long way from the overflow point as the system cools? (Without a large air volume present somewhere, this sounds unlikely....).
Bamber, if you're so sure the symptoms are caused by a blockage, perhaps you'd like to describe the mechanism that produces the symptoms described?
Or perhaps you don't have the technical competence to do that?
Croydoncorgi, an interesting theory that actually accounts for all the symptoms described, but would air trapped in a radiator really exert that much pressure when warmed by circulating water?
Or perhaps you don't have the technical competence to do that?
Croydoncorgi, an interesting theory that actually accounts for all the symptoms described, but would air trapped in a radiator really exert that much pressure when warmed by circulating water?
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